Nuclear Theory·nucl-th

Tuesday·July 3, 2018

11 papers—6 primary·5 cross-listed

07
[Submitted on 30 Jun 2018] (cross-list from hep-lat)
Transversity parton distribution functions from lattice QCD
Constantia Alexandrou🇨🇾 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Karl Jansen🇩🇪 · Aurora Scapellato🇨🇾 · Fernanda Steffens🇩🇪
We present the first direct calculation of the transversity parton distribution function within the nucleon from lattice QCD. The calculation is performed using simulations with the light quark mass fixed to its physical value and at one value of the lattice spacing. Novel elements of the calculations are non-perturbative renormalization and extraction of a formula for the matching to light-cone PDFs. Final results are presented in the $MS$ scheme at a scale of $2$ GeV.
Comments:
6 pages, 3 figures, 1 table
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1807.00232 [pdf]
PRD(2018)·163 citations
08
[Submitted on 1 Jul 2018] (cross-list from hep-th)
Holographic Magnetized Chiral Density Wave
Yanyan Bu🇨🇳 · Shu Lin🇨🇳
We explore the end point of the helical instability in finite density, finite magnetic field background discussed by Kharzeev and Yee [1]. The nonlinear solution is obtained and identified with the (magnetized) chiral density wave phase in literature. We find there are two branches of solutions, which match with the two unstable modes in [1]. At large chemical potential and magnetic field, the magnetized chiral density wave can be thermodynamically preferred over chirally symmetric phase and chiral symmetry breaking phase. Interestingly, we find an exotic state with vanishing chemical potential at large magnetic field. We also attempt to clarify the role of anomalous charge in holographic model.
Comments:
18 pages, 9 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1807.00330 [pdf]
CPC(2018)·8 citations
09
[Submitted on 2 Jul 2018] (cross-list from astro-ph.HE)
Constraints on the nuclear equation of state and the neutron star structure from crustal torsional oscillations
Hajime Sotani🇯🇵 · Kei Iida🇯🇵 · Kazuhiro Oyamatsu🇯🇵
We systematically examine torsional shear oscillations of neutron star crusts by newly taking into account the possible presence of the phase of cylindrical nuclei. In this study, we neglect an effect of magnetic fields, under which the shear oscillations can be damped by the magnetic interaction. First, by identifying the low frequency quasi-periodic oscillations (QPOs) observed in the soft-gamma repeaters (SGRs) as the fundamental torsional oscillations, we constrain the slope parameter of the nuclear symmetry energy, $L$ , for reasonable values of the star's mass $M$ and radius $R$ . Meanwhile, we find that the 1st overtone of torsional oscillations obtained for given $M$ and $R$ can be expressed well as a function of a new parameter $ς \equiv (K_{0}^{4} L^{5})^{1/9}$ , where $K_{0}$ is the incompressibility of symmetric nuclear matter. Assuming that the lowest of the QPO frequencies above 500 Hz observed in SGR 1806-20 comes from the 1st overtone, we can constrain the value of $ς$ . Then, for each neutron star model, such a value of $L$ as can be obtained from the observed low frequency QPOs translates to the optimal value of $K_{0}$ via the above constraint on $ς$ . Finally, its consistency with allowed values of $K_{0}$ from empirical giant monopole resonances leads to neutron star models with relatively low mass and large radius, which are qualitatively similar to the prediction in earlier investigations. This result suggests that $L ≃ 58 - 73$ MeV, even when uncertainties in the neutron superfluid density inside the phase of cylindrical nuclei are allowed for.
Comments:
accepted for publication in MNRAS
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1807.00528 [pdf]
MNRAS(2018)·52 citations
10
[Submitted on 2 Jul 2018] (cross-list from hep-ex)
A Fixed-Target Programme at the LHC: Physics Case and Projected Performances for Heavy-Ion, Hadron, Spin and Astroparticle Studies
C. Hadjidakis🇫🇷 · D. Kikoła🇵🇱 · J.P. Lansberg🇫🇷 · L. Massacrier🇫🇷 · M.G. Echevarria🇮🇹 · A. Kusina🇵🇱 · I. Schienbein🇫🇷 · J. Seixas🇵🇹 · H.S. Shao🇫🇷 · A. Signori🇺🇸 · B. Trzeciak🇳🇱 · S.J. Brodsky🇺🇸 and 20 other authors
We review the context, the motivations and the expected performances of a comprehensive and ambitious fixed-target program using the multi-TeV proton and ion LHC beams. We also provide a detailed account of the different possible technical implementations ranging from an internal wire target to a full dedicated beam line extracted with a bent crystal. The possibilities offered by the use of the ALICE and LHCb detectors in the fixed-target mode are also reviewed.
Comments:
LaTeX, 115 pages. v2: version submitted to Physics Reports. A few figures added and some text improved. v3: accepted for publication in Physics Reports
Subjects:
High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1807.00603 [pdf]
Phys.Rept.(2021)·128 citations
11
[Submitted on 2 Jul 2018] (cross-list from hep-ph)
The $Ω (2012)$ as a hadronic molecule
M. Pavon Valderrama🇵🇱
Recently the Belle collaboration has discovered a narrow $S = - 3$ baryon, the $Ω (2012)$ . We explore the possibility that the $Ω (2012)$ is a $Ξ (1530) K ˉ$ molecule, where the binding mechanism is the coupled channel dynamics with the $Ω η$ channel. The characteristic signature of a molecular $Ω (2012)$ will be its decay into the three body channel $Ξ π K ˉ$ , for which we expect a partial decay width of $2 - 3 MeV$ . The partial decay width into the $Ξ K ˉ$ channel should lie in the range of $1 - 11 MeV$ , a figure compatible with experiment and which we have deduced from the assumption that the coupling involved in this decay is of natural size. For comparison purposes the decay of a purely compact $Ω (2012)$ into the $Ξ K ˉ$ and $Ξ π K ˉ$ channels is of the same order of magnitude as and one order of magnitude smaller than in the molecular scenario, respectively. This comparison indicates that the current experimental information is insufficient to distinguish between a compact and a molecular $Ω (2012)$ and further experiments will be required to determine its nature. A molecular $Ω (2012)$ will also imply the existence of two- and three-body molecular partners. The two-body partners comprise two $Λ$ hyperons located at $1740$ and $1950 MeV$ respectively, the first of which might correspond to the $Λ (1800)$ while the second to the $Λ (2000)$ or the $Λ (2050)$ . The three-body partners include a $Ξ (1530) K K ˉ$ and a $Ξ (1530) η K ˉ$ molecule, with masses of $M = 2385 - 2445 MeV$ and $M = 2434 - 2503 MeV$ respectively. We might be tempted to identify the first with the $Ξ (2370)$ and the latter with the $Ω (2470)$ listed in the PDG.
Comments:
6 pages, 2 figures, corresponds to published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1807.00718 [pdf]
PRD(2018)·54 citations

Affiliations

first authorsco-authorsvia INSPIRE

Transversity parton distribution functions from lattice QCD

Holographic Magnetized Chiral Density Wave

Constraints on the nuclear equation of state and the neutron star structure from crustal torsional oscillations

A Fixed-Target Programme at the LHC: Physics Case and Projected Performances for Heavy-Ion, Hadron, Spin and Astroparticle Studies

The Ω(2012) as a hadronic molecule

Affiliations

The $Ω (2012)$ as a hadronic molecule